Browse Definitions :
Definition

dielectric material

 

A dielectric material is a substance that is a poor conductor of electricity, but an efficient supporter of electrostatic field s. If the flow of current between opposite electric charge poles is kept to a minimum while the electrostatic lines of flux are not impeded or interrupted, an electrostatic field can store energy. This property is useful in capacitor s, especially at radio frequencies. Dielectric materials are also used in the construction of radio-frequency transmission lines.

In practice, most dielectric materials are solid. Examples include porcelain (ceramic), mica, glass, plastics, and the oxides of various metals. Some liquids and gases can serve as good dielectric materials. Dry air is an excellent dielectric, and is used in variable capacitors and some types of transmission lines. Distilled water is a fair dielectric. A vacuum is an exceptionally efficient dielectric.

An important property of a dielectric is its ability to support an electrostatic field while dissipating minimal energy in the form of heat. The lower the dielectric loss (the proportion of energy lost as heat), the more effective is a dielectric material. Another consideration is the dielectric constant , the extent to which a substance concentrates the electrostatic lines of flux. Substances with a low dielectric constant include a perfect vacuum, dry air, and most pure, dry gases such as helium and nitrogen. Materials with moderate dielectric constants include ceramics, distilled water, paper, mica, polyethylene, and glass. Metal oxides, in general, have high dielectric constants.

The prime asset of high-dielectric-constant substances, such as aluminum oxide, is the fact that they make possible the manufacture of high-value capacitors with small physical volume. But these materials are generally not able to withstand electrostatic fields as intense as low-dielectric-constant substances such as air. If the voltage across a dielectric material becomes too great -- that is, if the electrostatic field becomes too intense -- the material will suddenly begin to conduct current. This phenomenon is called dielectric breakdown . In components that use gases or liquids as the dielectric medium, this condition reverses itself if the voltage decreases below the critical point. But in components containing solid dielectrics, dielectric breakdown usually results in permanent damage.

This was last updated in November 2010

Join the conversation

2 comments

Send me notifications when other members comment.

Please create a username to comment.

nice presentation.
could you tell me the difference of dielectric and ferroelectrical materials wrt relative permittivity. also give examples
Cancel
I think you should go for FR4
Cancel

-ADS BY GOOGLE

File Extensions and File Formats

SearchCompliance

  • compliance audit

    A compliance audit is a comprehensive review of an organization's adherence to regulatory guidelines.

  • regulatory compliance

    Regulatory compliance is an organization's adherence to laws, regulations, guidelines and specifications relevant to its business...

  • Whistleblower Protection Act

    The Whistleblower Protection Act of 1989 is a law that protects federal government employees in the United States from ...

SearchSecurity

  • Transport Layer Security (TLS)

    Transport Layer Security (TLS) is a protocol that provides authentication, privacy, and data integrity between two communicating ...

  • van Eck phreaking

    Van Eck phreaking is a form of electronic eavesdropping that reverse engineers the electromagnetic fields (EM fields) produced by...

  • zero-trust model (zero trust network)

    The zero trust model is a security model used by IT professionals that requires strict identity and device verification ...

SearchHealthIT

SearchDisasterRecovery

  • cloud insurance

    Cloud insurance is any type of financial or data protection obtained by a cloud service provider. 

  • business continuity software

    Business continuity software is an application or suite designed to make business continuity planning/business continuity ...

  • business continuity policy

    Business continuity policy is the set of standards and guidelines an organization enforces to ensure resilience and proper risk ...

SearchStorage

  • solid-state storage

    Solid-state storage (SSS) is a type of computer storage media made from silicon microchips. SSS stores data electronically ...

  • persistent storage

    Persistent storage is any data storage device that retains data after power to that device is shut off. It is also sometimes ...

  • computational storage

    Computational storage is an information technology (IT) architecture in which data is processed at the storage device level to ...

Close